BioPerspectives

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Jun 28, 2012

Working Toward Better, Cheaper Drug Discovery

Many of the technologies exhibited at this years’ European Lab Automation (ELA) in Hamburg are geared toward cutting assay costs, improving cell and tissue preparation, or speeding up cell analysis workflow. The mood at the conference was downbeat with few new product launches. Is this a reflection of the financially trying times in Europe at the moment or just the fact that all the instrument manufacturers had already had their product launches at Analytica, or were keeping their powder dry for ACHEMA?

Big Is Not Always Best

Sample preparation was one hot topic at ELA, with many companies now convinced that just having vast numbers of tissues or compounds is not enough for cost-effective and successful preclinical drug screening outcomes. “Having the biggest compound collection in the big pharma world has lots of pitfalls as well as advantages,” said Rose Gonzales, Ph.D., director of compound management and distribution at Pfizer. “We realized in 2009 that we had too many compounds that looked the same, and also many that we call uglies, which are reactive or unusable compounds. We set about better characterizing our collection, and by doing this have reduced our library by almost one million compounds.”

Mark Wigglesworth, Ph.D., manager of lead optimization sample management technologies at GlaxoSmithKline, added: “We also concluded in 2009 that our compound collection contained too many compounds with high lipophilicity, and we were running too many screens with undesirable compounds. This was a major task, but we have significantly enhanced our compound collection and used new software to help us cherry pick the right compounds from our libraries. By cherry picking many compounds, we’re now able to perform screens more efficiently instead of screening undesirable compounds, which when you’re screening hundreds of thousands of compounds becomes a substantial cost savings.”

Fail to Prepare, Prepare to Fail

“The number one roadblock to successfully screening tissues is the availability of high-quality samples, which haven’t experienced degradation or changes to the RNA and protein expression. While degradation is an issue, the main problem is an active change of RNA and protein profiles of cells caused by the surgical techniques used to remove the tissue, the drugs the patient is on, and most importantly how the tissue is prepared post-surgery,” stated Professor Hartmut Juhl, founder and CEO of Indivumed, a German firm that specializes in isolating and banking biological samples from patients suffering from bowel, lung, breast, and colorectal cancers.

Professor Juhl presented evidence to substantiate this claim, by showing how significantly the protein profiles of two different proteins isolated from 40 different cancer samples changed pre- and post-surgery. To overcome this problem, Professor Juhl explained that his company has designated nurses on surgical teams in eight cancer centers in Germany. These nurses prepare for surgery along with the surgical team, receiving information about a patient’s treatment and condition. When the tissue is removed, it is taken into a room next to the surgical suite, where it is sectioned into pieces that are then fixed and frozen within 5–10 minutes of being removed. Professor Juhl concluded: “We have 300 clinical data points on each tissue we collect and we now have over 15,000 patient samples. This is expensive and time consuming to do but we believe our process does provide tissues that are of high value in preclinical screening.”

Another new product featured at ELA was Cellectricon’s Cellaxess® Elektra Discovery Platform, for automated cellular electric field manipulation. Johan Pihl, Ph.D., product manager at Cellectricon, said, “The platform is highly versatile and can be used to transfect siRNA and cDNA into primary cell cultures in genomic screening applications. The system can also deliver small molecules and antibodies, and we believe it will enable scientists working with primary adherent cell types such as diffentiated neurons and cardiomyocytes in lead identification and target validation. The platform lets users perform in situ manipulation and monitoring of cell cultures directly in 96- and 384-well HCS compatible microplates without affecting viability and cellular morphology, enabling the manipulation and study of more biologically relevant cell systems such as primary and stem-cell derived cultures.

According to Dr. Pihl, Cellectricon is also offering access to the platform through its discovery assay development and discovery screening services. “The hybrid business model allows researchers in pharma/biotech and academia to acquire the Cellaxess Elektra platform for certain applications or to outsource to us for discovery screening services employing electric field manipulation of cells in CNS and cardiovascular applications,” he explained.

Cellaxess Elektra can also be configured with an integrated imaging-based microplate reader for recording of transient fluorescence and luminescence signals from living cells in real-time to provide data in CNS/pain and cardiovascular research applications. Cellectricon supplies a plate reader, but readers from other manufacturers could be integrated, and there were several available at ELA. One example was the HTS multi-mode microplate PHERAstar FS, which was exhibited by BMG LABTECH.

“Using the PHERAstar FS, cell-based microplate assays are now possible that were not possible before,” said Silke Angersbach, Ph.D., the firm’s regional manager. “When measuring cell-based assays on a microplate reader, it is necessary to measure from the plate bottom. Most instruments use flexible, inefficient fiber optics to measure from the microplate bottom. The PHERAstar FS, however, uses a Direct Optic Bottom Reading approach analogous to a microscope. Since fiber optics are not used, the overall signal is significantly higher (up to 10-fold) compared to instruments that use fiber optics.”

3D and Primary Cell Analysis—The Future?

With an estimated 30% of scientists looking at switching to using 3D and primary cell culture for screening by 2015, the number of technologies geared around analyzing whole cells was evident at ELA. The ImageXpress® Micro XL Widefield HCS System from Molecular Devices is an interesting new product for this. The company claims that the ImageXpress Micro XL microscope lets researchers image three times the area of its predecessors.

“We have built this ImageXpress system for digital, fully automated confocal microscopy,” noted Christian Holz, European application specialist, imaging. “It uses solid-state lighting and a very high-resolution, 16 bit SCMOS camera to enable the researcher to capture a field of view three times larger than previous generation instruments. This will be useful for applications such as imaging neural networks. The software has been upgraded to allow users to take ZED stacks and have more accurate information about 3-D cells in the stacks, as this is very much what scientists now need with their research.”

There is also a large database for image storage, Holz explained. “The images of 3D cells often require considerable storage space, so we have built a database that holds terabytes of information securely.”

High-content analysis of 3D cells was also discussed at ELA. “There’s lots of buzz around phenotypic screening, as over 60 percent of new first in class drugs that have emerged in recent years are from phenotypic screening using cell-based assays. So it makes sense to try and increase the throughput in sensitive techniques like flow cytometry,” explained Yen Kim Luu, Ph.D, manager, assay development at IntelliCyt, a U.S.-based manufacturer of screening solutions. “This is what we’re doing with our HyperCyt® high-content flow cytometry screening system.”

Dr. Luu described the levels of throughput that can now be achieved, stating that Pfizer has used a 384-well plate-based HyperCyt system in a toxicity screen to generate 50,000 data points over five days. The group screened 231 compounds for cardiac or hepatoxic effects and identified 21 different toxicity profiles.

“Using the HyperCyt technology does take scientists into real-world screening throughput because read times are only 3 minutes for 96-well plates or 12 minutes for 384-well plates,” Dr. Luu concluded. “This provides fast population phenotyping and the potential to more accurately screen thousands of compounds in disease-relevant assays. I believe we’re going to see an increasing number of high-throughput technologies for 3D cell analysis being developed and used more extensively in drug screening in the next decade.”

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